RFO Commercial V7

Elemental LCC and options appraisal timing - KBCN1889

The elemental LCC should be undertaken as part of the strategic options appraisal process and used to inform the selection of significant building elements and systems, such as the structure, envelope and building services. Completing the options appraisal after key design decisions have been finalised may reduce its effectiveness and limit the opportunity for the findings to influence the final design. However, the timing requirement can still be met, where the assessor agrees that there is a justification for the appraisal continuing into early AIA Stage 2 - Schematic Design (or equivalent), and clear evidence to demonstrate that:

• The key options remained under consideration during the appraisal.
• The findings were capable of influencing the final design solution.
• The intended outcomes of the elemental LCC process have not been compromised.

In all cases, the outline elemental LCC plan and identification of relevant project options must be completed by the end of Concept Design

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Life Cycle Assessment – Similar buildings approach (GN20 – Section 4) - KBCN1834

Where multiple buildings are included within the scope of a single BREEAM assessment following the Similar Buildings approach, in accordance with Section 4 of GN20, unless identical, each building must be assessed and reported separately within the LCA.  Where all buildings are demonstrably identical in design and specification (and differ only in scale), a representative LCA approach may be used (see KBCN1890). Shared elements (e.g. substructure, external works, or building services serving multiple buildings) may be apportioned between buildings using a reasonable and transparent method (e.g. by gross internal area or other appropriate project-specific metric), in line with recognised industry approaches. For the purposes of BREEAM benchmarking under Mat 01: • The results submitted to the platform must represent a single building, not a combined site-wide result. • Where multiple buildings are included within an assessment, the worst-performing building (in kgCO₂e/m²) must be used for benchmarking in line with the Similar Buildings methodology (section 4.2 of GN20). Full evidence must be provided to demonstrate: • That all buildings within scope of the assessment have been included, with individual LCAs completed for each building, and • How results have been separated and, where relevant, how shared elements have been allocated.

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Rationale: In line with Section 4.2 of GN20, BREEAM issues must be assessed for each individual building, with credits awarded based on the worst‑performing building for each assessment issue. The Similar Buildings approach therefore remains an individual‑building assessment methodology and does not constitute a site‑wide assessment, even where multiple buildings are included.

09.07.2026 Reference to KBCN1890 added

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Life Cycle Assessment – Similar buildings with identical design (GN20 Section 4) – Representative LCA approach - KBCN1890

Where multiple buildings are substantially identical in design, construction and specification, and any differences are limited to scale, a representative LCA approach may be used instead of completing a full LCA for every building. Where buildings are not substantially identical, see KBCN1834. For the purposes of BREEAM benchmarking under Mat01:

• A representative LCA and a single options appraisal may be applied across all buildings, provided that all specifications (including scoped elements) are consistent and carbon reduction measures are specification-driven rather than scale-dependent.
• Robust justification and supporting evidence must be provided to confirm representativeness. The representative model should normally be the largest, most carbon-intensive, or otherwise demonstrably representative building within the development.
• Results must be expressed in normalised form (e.g. kgCO₂e/m²) and demonstrated to be applicable across all units, with any variation in outcomes shown to be not materially significant (e.g. within ±10%).
• Shared elements (e.g. substructure, external works, or building services serving multiple buildings) may be apportioned between buildings using a reasonable and transparent method (e.g. by gross internal area or other appropriate project-specific metric), in line with recognised industry approaches.

Demonstrating representativeness does not require full LCAs for additional units; proportionate methods such as parametric scaling of quantities or elemental intensity comparisons may be used to evidence that variation in normalised results is not materially significant. Where there is uncertainty regarding representativeness, a secondary check model for an additional unit is recommended to verify consistency of results.

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Rationale: The representative LCA approach provides a proportionate means of assessing developments containing multiple highly similar buildings while maintaining confidence that reported results are representative of individual building performance. It is intended as a limited exception to the standard requirement for building-specific assessment.

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Outside space – Disturbance from sources of noise - KBCN1888

The requirements set out in the Definitions must be met in as far as is practicable, considering any specific site constraints. For some developments, particularly industrial or large retail sites, it may not always be possible to avoid areas that will have disturbance from sources of noise. In such cases, the project team must provide justification, with reference to a marked-up site plan, to demonstrate that the outdoor space is situated the most appropriate available area and meets the requirements as far as possible. Where the use of the outdoor space is compromised by unavoidable disturbance from sources of noise, the project team must seek to mitigate this where it is practical to do so, for instance through the introduction of screening or planting. It is the role of the assessor to review the approach taken and determine whether, accounting for any mitigation measures and residual disturbance, the outdoor space provides a practical and comfortable amenity that is suitable for its intended use.

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